LOS ANGELES - As investigators scour the Los Angeles International Airport terminal for evidence into what could have been a massive kill zone Friday, the nation's third-busiest airport was heading back toward normal operations Saturday.

Most of LAX was functioning early Saturday after 1,550 flights, including 724 arrivals and 826 departures, were either canceled or diverted by Friday's shootings. Departing passengers were tweeting early Saturday that there were few problems accessing the airport. Still, LAX officials urge passengers to check with airlines for potential departure and arrival delays. Those who left luggage at Terminal 3 during Friday's mayhem aren't able to recover their belongings yet.

Ciancia, 23, was shot four times by airport police and remains hospitalized. Aside from Hernandez and the two wounded TSA officers, a person suffered a broken ankle.

The carnage could have been far worse, investigators say. Police say the shooter, armed with a semi-automatic rifle, brought 150 rounds of ammunition to the airport. Investigators recovered a rambling message from the bag the shooter was allegedly carrying, which detailed an intent to "kill" TSA officers, said two federal law enforcement officials familiar with the message's contents. The officials, who are not authorized to comment publicly, said it was written in a way that suggested the author expected to lose his life.

Terrified witnesses say the suspect also asked them whether they worked for the TSA.

Leon Saryan told ABC News that the gunman approached him and pointed a long-barreled gun at him.

"I was cowering in a corner, he looked at me and he said, 'TSA?' I shook my head no, and he kept on going," Leon Saryan said. "I just prayed to God. That's all I did. I just prayed," Saryan said.

In recent days, one of the officials said, the New Jersey family of the alleged shooter had become worried about his emotional state and called local police, who relayed their concerns to Los Angeles authorities. The official said Los Angeles police reportedly were in contact with the alleged shooter's roommates, who indicated that he appeared to be OK.

According to a report by the Associated Press, a law enforcement source said the gunman's note referred to how he believed his constitutional rights were being violated by TSA searches and that he was a "pissed-off patriot" upset at former Homeland Security Secretary Janet Napolitano.

The suspect entered Terminal 3, pulled out an assault rifle from a bag, then began to open fire at a screening checkpoint, according to LAX Police Chief Patrick Gannon. He then proceeded up to a screening area, where he continued shooting, then went past the screeners back into the airport itself, Gannon said. He continued to move along a terminal corridor until apprehended at a Burger King in the food court, where airport police officers shot him four times, including in the mouth and leg. There was no word on his condition.

Police check the area around Terminal 1 at Los Angeles International Airport on Nov. 1, 2013. A gunman armed with a semiautomatic rifle opened fire at the airport killing a Transportation Security Administration employee and wounding other people. Reed Saxon, AP

Hernandez is the first TSA officer killed in the line of duty in the 12-year history of the agency, created after 9/11. Another victim was listed in critical condition, and at least two of the injured were TSA employees.

Friends and neighbors remembered Hernandez as a doting father of two and a good neighbor.

Before arriving in the LA area, Ciancia lived with family in a quiet, wooded neighborhood in Pennsville, N.J., police said.

Joshua Pagan, 17, has lived across the street from Ciancia's residence in Pennsville for the past 10 years. He said Ciancia has a brother close in age to him.

"I've seen (Paul) a few times, but I did not know him personally," Pagan said. "From what I've seen and heard, he was just a normal person - just an every-day guy. Right now, I am still trying to process this. Did this really happen? Did they get the wrong guy? Because if they told me they got the wrong guy, it would make a lot more sense to me."

The shooting left much of the nation's third-busiest airport shut and the surrounding area in gridlock. The Federal Aviation Administration canceled or diverted 746 flights. Airport roadways were closed. Travelers were stuck on incoming and departing planes on the tarmac, on buses or sidewalks.

Monitored in real-time by scores of terrified bystanders on social media websites such as Twitter and Instagram, the incident was the latest in a recent spate of mass shootings. Some passengers built walls of luggage to protect themselves from flying bullets. Others fled through emergency doors and onto the tarmac, including some who were briefly handcuffed and questioned by swarming groups of police before they were released.

"They probably thought I was the shooter. They handcuffed me and told me not to move," said Nick Pugh, who was attempting to fly to New York to watch Sunday's New York Marathon.

Aleksander Fiksdal, 22, was in a security checkpoint line for a flight to his native Norway when he heard shots ring out. "I turned and saw a guy with a rifle and I threw myself on the ground," Fiksdal said. Other passengers in the security line did the same, while some broke and ran.

"I really thought I saw death," said Anne Rainer, who witnessed the gunfire with her 26-year-old son Ben. The pair were about to leave for New York so her son could see a specialist for a rare genetic condition he has.

They took refuge behind a ticket counter where she said people prayed, cried and held hands. She watched as one person jumped from a second-floor balcony to get away from the gunman.

"Adrenaline went through my head, my body went numb, and I said, 'If I have to go, it's OK because I'm not going to feel it, but I have to save him,'" Rainer said.

Friends Mara Allen, 42, of Yuba City, Calif., and Vicki Powell of Sacramento had just arrived on a flight so they could go on a cruise to celebrate Powell's 50th birthday. Gathered with others around a baggage carousel, they were startled when a police officer started yelling for people to flee. Wheelchair-bound Powell wasn't sure how she was going to get out.

"I was waving. Come get me. Help!" Powell caught the attention of an attendant who wheeled her outside. The pair had to leave their luggage behind, and it was unclear whether they'd be able to retrieve it before their ship leaves LA for Mexico. "This is something I see on TV. I don't want to be in it," Powell said.

Among the people evacuated from the airport, more than dozen were treated for minor injuries such as twisted ankles, exhaustion or stress.

The Radisson Hotel close to LAX was turned into a makeshift refugee center crammed with passengers. One large group gathered around a television set in the bar, where a clot of them were glued to coverage of the unfolding drama.

The last shooting at the airport occurred in July 2002, when an Egyptian immigrant shot and killed two bystanders in a rampage at the El Al ticket counter.